It's possible that you could wake up on Earth right now and still not recognize the planet. That's because of the incredible diversity of species. Habitats that you've never encountered would be inhabited by organisms that you've never seen or known about.

There are more than 1 million species of plants and animals known to be currently alive on Earth (
Figure
below
) and many millions more that have not been discovered yet. The tremendous variety of creatures is due to the tremendous numbers of habitats that organisms have evolved to fill.

There is an amazing diversity of organisms on Earth. How do the organisms in this picture each make their living?

Adaptations

Cacti have thick, water- retaining bodies that help them conserve water.

Other adaptations help an organism move or gather food. Reindeer have sponge-like hoofs that help them walk on snowy ground without slipping and falling. Hummingbirds have long, thin beaks that help them drink nectar from flowers. Organisms have special features that help them avoid being eaten. When a herd of zebras run away from lions, the zebras’ dark stripes confuse the predators so that they have difficulty focusing on just one zebra during the chase. Some plants have poisonous or foul-tasting substances in them that keep animals from eating them. Their brightly colored flowers serve as a warning.

Poison dart frogs have toxins in their skin. Their bright colors warn potential predators not to take a bite!

Thousands of northern elephant seals — some weighing up to 4,500 pounds — make an annual migration to breed each winter at Año Nuevo State Reserve in California. Marine biologists are using high-tech tools to explore the secrets of these amazing creatures.